Electronic devices, such as laptop computers, smartphones, portable gaming devices, tablets, or others, require power to operate. As generally understood, electronic devices are often charged at least once a day, or in high-use or power-hungry electronic devices, more than once a day. Such activity may be tedious and may present a burden to users. For example, a user may be required to carry chargers in case his electronic devices run out of power. In addition, some users have to find available power sources to connect to, which is inconvenient and time consuming. Lastly, some users must plug into a wall or some other power supply to be able to charge their electronic devices. Such activity may render electronic devices inoperable or not portable during charging.
Some conventional solutions include an inductive charging pad, which may employ magnetic induction or resonating coils. As understood in the art, such a solution still requires the electronic devices to: (i) be placed in a specific location on the inductive charging pad, and (ii) be particularly oriented for powering due to magnetic fields having a particular orientation. Furthermore, inductive charging units require large coils in both devices (i.e., the charger and the device being charged by the charger), which may not desirable due to size and cost, for example. Therefore, electronic devices may not sufficiently charge or may not receive a charge if not oriented properly on the inductive charging pad. And, users can be frustrated when an electronic device is not charged as expected after using a charging mat, thereby destroying the credibility of the charging mat.
Other solutions use far field RF wave transmission to create pockets of energy by constructive interference of RF waves at remote locations for charging a device. Such solutions, however, are better suited for particular uses and configurations as far field RF wave transmission solutions typically use numerous antenna arrays and circuitry for providing phase and amplitude control of the RF waves. Furthermore, far field antennas may not be efficient for near-field charging systems. Some antennas such as patch antennas have been used for near-field power transfer. However, the patch antennas also have low power transfer efficiency in near-field, particularly as the generated power may leak in all directions, rather than being concentrated in a particular area in near-field.
Therefore, there is a need in the art to address the above described drawbacks of far field antennas and near field antennas and construct near RF field antennas with high coupling efficiency.